Furnace



FURNACE Filed Oct. 21, 1935 0J'car 14. Jo/vworz.

Patented May 24, 1938 UNITED STATES PATENT OFFICE FURNACE Application October 21, 1935, Serial No. 45,849

7 Claims.

This invention relates to furnaces, and more particularly to furnaces of the chain grate or traveling grate type in which the fuel is supported for combustion upon the upper run of an endless grate.

In furnaces of this type air frequently enters the furnace along the sides of the grate in excessive quantities, causing rapid combustion of the marginal portions of the fuel bed and undesirable dilution of the gaseous products of combustion. Great difficulties have been encountered in overcoming this problem, despite numerous attempts which have been made in the past to reach a solution. The growth and distortion which usually take place in the grate after prolonged use have complicated the problem.

It is accordingly the main object of the present invention to provide a furnace of the endless grate type which is soconstructed and arranged as to prevent excessive flow of air into the furnace at the sides of the grate.

It is a further object of the invention to provide a furnace of the endless grate type having a simple, inexpensive and durable means for preventing excessive air flow into'the furnace at the sides of the grate, and particularly to provide an air sealing means which will remain effective regardless of growth and distortion of the grate.

With these and other objects in view, as will be apparent to those skilled in the art, the inven tion resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

Referring to the drawing illustrating one embodiment of the invention, and in which like reference numerals indicate like parts,

Fig. 1 is a transverse section through the marginal portion of a furnace of the endless grate 40 type;

Fig. 2 is an enlarged view of a portion of Fig. 1; and

Fig. 3 is a perspective view of a ledge plate.

The embodiment illustrated comprises an end- 45 less grate having an upper run Ill and a lower run 1 i. This grate is formed by rows of comparatively small grate members or clips l2 mounted on transverse supporting bars M. The bars M are carried by endless chains l5 (one 50 only being shown) which rest on upper and lower tracks l6 and H secured to transverse beams IS. The ends of the beams I9 are supported by side frames each comprising an upper longitudinal channel member 20, a lower longitudinal channel 5 member 2|, and an angle member 23 mounted on the top of the member 20. An angle member 25 is secured to the inner side of the upper channel member 20 and provides a horizontal flange or shelf projecting inwardly therefrom beneath the marginal portion of the upper grate 5 run it]. At the end of each row of grate clips l2 and supported by bar M there is provided a sealing clip 25 having a vertical flange 26 extending downwardly therefrom into close proximity with the angle member 241. A substantial space 21 is 10 provided between the sealing clips and the side frames, so that the grate may expand freely in a lateral direction.

The furnace chamber is enclosed at each side by a wall 29 of refractory material, the inner l5 portion of this wall being supported by a series of ledge plates 30 which project inwardly above and close to the marginal portion of the upper grate run 10. The ledge plates 30 are supported in part by the angle member 23, which engages 20 a groove 3! in the lower surface of each plate and thus holds the plates in alignment. The outer portions of the ledge plates are supported by a wall 33 therebeneath which rests upon a concrete foundation 3 3. The wall 33 is provided 25 with one or more openings 35 through which air may be admitted into the space beneath the grate.

The flanges 25 cooperate with the shelf 24 to restrict the flow of air upwardly around the side 30 of the grate, but this construction does not provide an effective seal. In order to substantially eliminate this marginal leakage of air, I preferably provide elongated sealing members which rest upon the upper surface of the grate and 35 which are prevented from moving laterally by means of the ledge plates.

In the embodiment illustrated each ledge plate is formed with inner and outer horizontal portions located in substantially the same plane and connected by a portion 3'! shaped as an inverted U in cross-section. This portion 31 provides a downwardly opening groove or recess 38 in the lower surface of the ledge plate. Beneath the ledge plate there is provided a member 39 comprising an upwardly extending vertical flange 4| which fits loosely in the recess 38 and an inwardly extending horizontal flange 42 which rests upon the upper surface of the grate. A rib 43 projects downwardly from the inner edge of each ledge plate nearly into contact with the grate.

The furnace side wall 29 is constructed for the most part of preformed bricks of a standard size and shape, but it is difiicult to hold such bricks securely in position at the inner side of on the inner surface of each portion 31, these projections interlocking with refractory material 46 which is preferably applied in a plastic condition and subsequently dried and baked by the heat of the furnace.

The operation of the invention will now be apparent from the above disclosure. Fuel is carried slowly into the furnace by the upper grate run ID in the usual manner. Air is admitted through the openings 35 preferably under forced draft, and the grate clips l2 distribute the air throughout the fuel bed and thus promote combustion of the fuel. The sealing member 39 rests by gravity in sliding contact with the grate clips therebeneath, and the horizontal flange 42 provides a large contact area which avoids excessive wear from the rubbing action. The grate clips are free to expand laterally into the space 21, and regardless of such expansion the sealing member 39 will remain effective to prevent leakage of air around the margin of the grate. It will be apparent that the leakage path between the ledge plates 30 and the sealing member 39 is so tortuous and so restricted that very little air can escape therethrough.

' The construction is simple and inexpensive, and may be easily applied to existing installations.

r Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A furnace comprising an endless grate having an upper run and a lower run, the upper run having a'substantially fiat upper surface, a ledge plate projecting inwardly above the marginal portion of the said flat surface, a furnace wall supported onthe ledge plate, the ledge plate being shaped to provide 'a downwardly opening recess in itsilower surface, and a sealing member mounted in the recess and resting by gravity on the marginal portion of the said flat surface to prevent leakage of air inwardly beneath the ledge plate.

2. A furnace comprising an endless grate having an upper run and a lower run, a frame at the side of the grateand spaced therefrom to allow lateral expansion of the grate, a ledge plate resting on the frame and projecting inwardly above the marginal portion of the upper grate. run, a furnace wall supported on the ledge plate, the ledge plate being shaped to provide a downwardly opening recess in its lower surface, and a sealing member mounted in the recess and resting by gravity on the marginal portion of the upper grate run to prevent leakage of air inwardly beneath the ledge plate.

3. A furnace comprising an endless grate having an upper run and a lower run, a ledge plate projecting inwardly above the marginal portion of the upper grate run, a furnace wall supported on the ledge plate, the ledge plate being shaped to provide a downwardly opening recess in its lower surface, and a sealing member having a flange which extends upwardly into the recess, the sealing member resting by gravity on the marginal portion of the upper grate run to prevent leakage of air inwardly beneath the ledge plate.

4. A furnace comprising an endless grate having an upper run and a lower run, a ledge plate projecting inwardly above the marginal portion of the upper grate run, a furnace wall supported "on the ledge plate, the ledge plate having an inner and an outer portion connected by a portion shaped as an inverted U in cross-section to provide a recess, and a sealing member positioned in the recess and resting by gravity on the marginal portion of the upper grate run to prevent leakage of air inwardly beneath the ledge plate.-

5. A furnace comprising an endless grate having an upper run and a lower run, a ledge plate projecting inwardly above the marginal portion of the upper grate run, a furnace wall supported on the ledge plate, the ledge plate being shaped to provide a recess in its lower surface, and an angle member having an upwardly extending vertical flange located in the recess and an inwardly extending horizontal flange resting by gravity on the marginal portion of the upper grate run to prevent leakage of air inwardly beneath the ledge plate.

6. A furnace comprising an endless grate having an upper run and a lower run, a ledge plate projecting inwardly above the marginal portion of the upper grate run, a furnace wall supported on the ledge plate, the ledge plate having an inner and an outer portion connected by a portion shaped as an inverted U in cross-section to provide a recess, and an angle member having an upwardly extending vertical flange located in the recess and an inwardly extending horizontal flange resting by gravity on the marginal portion of the upper grate run to prevent leakage of airinwardly beneath the ledge plate.

7. A furnace comprising an endless grate having an upper run and a lower run, a ledge plate projecting inwardly above the marginal portion of the upper grate run, a furnace wall supported on the ledge plate, the ledge plate having two substantially flat horizontal portions and a connecting portion joining the horizontal portions, the connecting portion being shaped as an inverted U in cross-section to provide a recess, a sealing member positioned in the recess and resting by gravity on the marginal portion of the upper grate run to prevent leakage of air inwardly beneath the ledge plate, and means on the ledge plate to interlock with that part of the furnace wall which is located at the inner side of the said connecting portion.

OSCAR A. JOHNSON. 

